Concurrent with the HIV/AIDS epidemic, the United States is facing an epidemic in sexually transmitted diseases (STDs). The rising STD incidence rates are of great concern because many of these diseases cause ulcerations which may facilitate sexual transmission of HIV. Research must focus greater attention on behavioral and psychological factors thought to influence the actions of people at elevated risk of HIV infection, such as those with STD histories. With an improved understanding of how these factors affect behavior, researchers and educators may be better able to design interventions which promote realistic assessments of HIV risk and safer sexual practices. The proposed study examines the degree to which cognitive, motivational, and behavioral factors are associated with perceptions of vulnerability to STD/HIV infection, intentions to adopt preventive behaviors, and actual sexual behavior. The study will further the understanding of perceptions of vulnerability and their link with risky sexual behavior among those at risk-of HIV infection, such as those with STDs. Additionally, the proposed study tests a path model which examines not only main-effect relationships among variables, but also interaction effects. The examination of such interactions goes beyond past analytic approaches which have typically examined variables in statistical isolation from one another. Results from this study can be directly applied to the development of culturally- sensitive STD/HIV risk reduction interventions for STD clinic attenders, people of color, and other at-risk populations. The study will be conducted with a multiethnic sample of adult men and women presenting at a public STD clinic in Los Angeles. Two waves of data will be collected. At Time 1, subjects self-administer a confidential survey measuring psychological/behavioral variables; a medical chart review is also performed. The Time 2 assessment, conducted by phone, occurs 6 weeks after the Time 1 survey and measures sexual behaviors which occurred since the clinic visit. Subjects will be recruited without regard to ethnicity, gender, or sexual orientation. The sample will include men and women 18 years of age or older who are able to provide informed consent, and who speak English or Spanish. Subjects will be recruited in the clinic waiting area by a bilingual research assistant trained in data collection procedures. Based on information from clinic providers regarding attendance rates and participation rates obtained by other clinic-based studies, we anticipate a total sample of 336 individuals after 20 weeks of recruitment. Those wishing to participate will be consenting to a confidential self- administered questionnaire, a medical chart review, and a brief telephone follow-up 6 weeks after initial recruitment. The telephone follow-up will be done using the phone number provided by the subject at the time of study enrollment. Data will be analyzed with stratified, descriptive procedures. Tests of main effects and moderation hypotheses will be done using multiple regression analyses.